IXTRODUCTION. 5 



on the right, aud varying considerably in form. Beyond 

 this the oesophagus contiuues for a short distance as a 

 narrow tube, and then dilates into the second or chyle 

 stomach. The chyle stomach also receives the urinary 

 vessels near its apex. Beyond the chyle stomach extends 

 the smaller intestine which widens out posteriorly into the 

 colon, which again narrows to the apical opening of the 

 abdomen. The sides of the colon internally are usually 

 strengthened by longitudinal plates varying in form and 

 number, but in the genus Bomhxi^, Dufour says there is no 

 trace to be found of this character. 



Salivary Si/stem. — The salivary glands in the Hymen- 

 optera play a very important part in their economy, and in 

 the hive bee are very largely developed. Some of these lie 

 in the head, some in the thorax. The pharynx beneath is 

 chitinized into a slightly concave plate called the hypo- 

 pharangeal plate, near the front margin of which are two 

 nipple- like openings, which lead into the salivary ducts, 

 these diverge laterally into two systems of glands that lie 

 near the centre of the head. Behind these are two other 

 lateral systems in the head, and two more lying in the 

 thorax; these latter four unite into one common duct, 

 which terminates in a valvular opening near the base of 

 the tongue on its upper surface. This description is taken 

 from the ? of the houey bee; pi-obably modifications of 

 these systems would occur in many of the families. Leon 

 Uufour fails to find any salivary glands in some of the 

 Fossores. At the base of each mandible there is a small 

 gland, but there seems to be doubts as to its functional use. 



The Nervous Sytiieia, as in other insects, consists of a 

 system of ganglia united along the centre of the insect by 

 two longitudinal cords, from which ganglia nerves are 

 distributed to the various organs. The cephalic ganglia 

 are largely developed ; there are five or six abdominal 

 ganglia, the rest being thoracic. 



The Circninforii Si/stnn consists of a dorsal vessel, \vhich 



